Question: How many feet of baseboard do I need to heat a room 57ft/21ft 9ft high.
Answer: A basic rule of thumb is, 10 watts per square foot. Your room is approximately 1200 square feet. You will need 12,000 watts of baseboard heater. When wired for 240-volt operation, a baseboard heater puts out 250 watts per foot. So a 6-foot long heater will give you 1500 watts.